The present invention relates to a copier, facsimile apparatus, printer or similar image forming apparatus and, more particularly, to an image forming apparatus having developer transporting means implemented by an electrostatic actuator which transports the particles of a developer having a predetermined charge in a predetermined direction.
An electrostatic actuator for the above application and implementing toner transporting means for transporting a toner from a developing unit to an image carrier is disclosed in, e.g., Japanese Patent Application No. 195901/1991. Specifically, the toner transporting means in the form of a developing roller has a stationary or unrotatable base roller. A plurality of stripe-like electrodes, or drive electrodes as referred to hereinafter, are formed on the base roller to extend in the axial direction of the roller. The nearby drive electrodes are each connected to particular one of a first to a third electrode terminal to constitute three drive electrode groups. Drive voltages of three different kinds and having a predetermined period are selectively applied to the electrode terminals associated with the three drive electrode groups. As a result, a time-varying electric field is formed in the vicinity of the drive electrodes to sequentially transport a charged toner around the drive electrodes in a predetermined direction.
However, the conventional electrostatic actuator described above is severely restricted in respect of design and expensive.